1. Field of the Invention
The present invention is an apparatus and method for filtering particulate matter from dielectric fluids, and for maintaining and monitoring of the purity of said fluids. The invention works with dielectric fluids used for combustion, lubrication and compression in pressurized systems.
2. Art Background
Numerous methods, compositions, devices and apparati have been conceived for the removal of fine particulate contaminants from dielectric fluids. Prior electrostatic filtration devices have embraced the concept of passing the fluid sought to be purified over, around or through charged electrodes. In the prior art it is known that porous filter media may be located along or between oppositely charged adjacent electrodes to trap fine particles, the susceptibility of which to deposition within said media is enhanced by the electrostatic charge of the particles. Alternatively, the prior art demonstrates that the filter medium itself may be charged to enhance collection of the particulates sought to be removed.
Most of the inventions of the prior art teach the flow of the dielectric fluid through a vessel which is in some manner punctured in order to allow the passage of electrical current from an external current source through the wall of the vessel. This punctured-vessel design has prevented the development of inexpensive or easily mass produced filters in a design capable of withstanding high pressure without fluid leakage. Such prior art filters could not be inexpensively constructed and also purify dielectric fluids under pressure without resorting to a bypass system whereby the fluid is bled or trickled away from the primary path to a filter located off the high pressure line. These bypass system prior art filters do not teach the placement of the filter in the primary fluid stream on the high pressure side of a pressurized system.
For example, in Watson, U.S. Pat. No. 4,302,310, the central charging module is of radial configuration, with perforated walls. Watson requires a nut to perform the function of fluid containment. The same assembly attaches the electrodes and contains the fluid.
Thompson, U.S. Pat. No. 4,594,138, depicts likewise a cylindrical housing in which the cylinder wall of the fluid containment housing contains studs connecting the alternately charged plates. This necessitates the perforation of the wall of the containment vessel. The failure of this design, as in Watson, to segregate the fluid containment function from the charging apparatus makes this design impossible to let the charging of the fluid accomplished by a separate disposable unit.
Griswold, U.S. Pat. No. 3,544,441 allows by design for a separation of the charging element from the fluid containment vessel. There is a central disposable filter pack which is removable, as in the present invention. The difference, however, is due to the fact that Griswold is a radial filter, which poses a major disadvantage. The Griswold filter allows the fluid to pass radially through the filter medium and along the electrode plates, which results in a single pass through the porous medium before the fluid exits through the outlet of the container.
Thus, no filter in the prior art allows for multiple charging via a filter element which is independent of the need to perform the function of fluid containment.
The lack of a cheap disposable module containing the porous filter medium in the prior art has not made it possible to systematically collect and recover the particulate matter contained therein without complicated disassembly of the wired electrodes. This has made the recycling of metals and other particulates contained in the porous medium of the filters described in the prior art a time-consuming and impractical task.
All of the filters in the prior art charge the fluid passing therethrough with a plurality of electrodes, which must be wired together either in series or in parallel. This electrical wiring requirement poses the risk of short circuits and/or broken circuits. The wiring of the prior art filters has presented difficulties in fabrication in that a buss bar, wire or other separate electrical attaching system is required to link together the plurality of electrodes.
Watson, for example, involves a rather complicated system of electrical connection. FIG. 3 and 4 of the drawings of Watson depict the conduction path. At 106a the electrode is attached to a stud, 117. This requires a separate attachment process. This design also requires the piecemeal composition, building block style, of the housing due to the need to place the annular rings or foam and electrodes in one at a time.
Thompson, likewise, accomplishes electrostatic charging via a pair of bus bars which are connected to each individual plate with pins (Thompson, FIG. 3 at numbers 54, 68, 72, and 50.)
The same can be said of Griswold. At page four, lines 33 through 44, a system of numerous electrical connecting components is described.
While many of the electrostatic filters of the prior art have been effective in the removal of fine particles, all have suffered from the lack of any control mechanism to monitor and operate them. This fact has limited the availability of electrostatic filtration in mobile and remote applications, as well as in fixed applications where changing conditions of use would make desirable real time or recurrent monitoring and ongoing control.
Therefore, it would be useful to provide an improved electrostatic filter which could be used in the high pressure lines of high pressure systems; which could utilize a replaceable element of simple, reliable, and inexpensive construction which need not itself be pressure resistant, and which could be fabricated without the need for any wiring; which could contain a module containing the trapped particulates which is easy to access and disassemble; and which could give feedback allowing its status to be monitored and its operation controlled cybernetically and in real time, in remote, in fixed, and in portable applications.